A Reminder to Patent Drafters: Consistent and Well-Defined Terminology Is Important

Because the patent specification inconsistently referred to, and failed to define, a critical claim term, the court granted a motion for summary judgment of indefiniteness under 35 U.S.C. § 112, ¶ 2, concerning claims of U.S. Patent No. 5,463,374Signal IP, Inc. v. Mazda Motor of North America, Inc., (C.D. Cal. Nov. 2, 2015.)  The plaintiff argued that the phrase "data format" in the claims would have been understood by those skilled in the art.  Unfortunately for the plaintiff, the patent specification used four different "format" terms, never defined "data format," and, confusingly, both distinguished and conflated "data format" with other the other terms.

Independent claim 1 of the '374 patent recited in part "the remote transmitters all having the same data format but distinctive codes for tire transmitters and vehicle function transmitters."  The specification never defined "data format," but described a "pulse width modulated" data format in conjunction with Figure 3.  The specification also stated that "[b]oth the data format and the message format are compatible with that of fob 16."  Figure 4 purported to show a "message format," but the plaintiff argued that this was obviously an error and should have referred to the "data format."  Compounding the confusion was that the specification first said that "data format" and the "message format" were the same, and then it said they were not.

The court declined to correct the error in the specification alleged by the plaintiff because the proposed correction did not meet the test of not being subject to reasonable debate.  Moreover, even if the plaintiff's proposal were not subject to reasonable debate, it would not have cured the indefiniteness.  The specification did not disclose the meaning of "data format."  Compounding the confusion were ill-defined references to "signal format" and "communication format."

The take-away here probably seems simple: make sure critical claim terms are defined and consistently used in the specification.  In practice, practitioners know that sometimes this dictum can be surprisingly difficult to implement, which is all the more reason to keep in mind train wrecks like this patent specification when drafting applications.

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